Fix General and Special General election display on election search page

[patphongs]

Issue

Since Gs and SGs can happen on the same day, sometimes G is populated and sometimes SG is populated. The problems are

1. They're both right
2. They're both in the API
3. The results don't populate predictably - it can flip back and forth between showing the G and the SG.

Updated business rules

These updated business rules are intended to untangle display of G vs SG elections.

If the General (G) and Special General(SG) elections are on on the same day, we want to show both at the same time.

• Display should be General/Special general election within the same result item

Otherwise, just show the next upcoming election, whether it's a G or SG.

• Display should be General election OR Special general election